ASTRO 2017: Biologic Markers of Primary Breast Cancer and Brain Metastases
One out of five patients with breast cancer and brain metastases had a marker discrepancy between the primary tumor and subsequent brain metastasis, according to research presented by Orit Kaidar-Person, MD, of the University of North Carolina Chapel Hill, and colleagues at the 2017 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 1003). The majority of patients in the sample had primary HER2-enriched tumors, followed by a triple-negative profile.
The investigators believe their study findings may have clinical implications for choice of systemic therapy in this patient population, given the contribution to nonresponsiveness to systemic therapies in the central nervous system. “In these cases, obtaining central nervous system tissue and receptor status may guide deciding on further therapy,” they indicated.
Retrospective data were collected from 167 breast cancer patients with brain metastases across 11 institutions. The team investigated discordances in the estrogen receptor, progesterone receptor, and HER2 expression between the primary tumor and the brain metastasis. Of 119 patients (71%) who had full receptor information of both primary tumor and brain metastases, 25 (21%) had a change in receptor status. The most common change was a loss of estrogen receptor/progesterone receptor or HER2 positivity.